musty smell from vents when first started up

I have been out of town for a couple of weeks and have not driven my 2000 996 coupe. Started it up yesterday and had a relatively strong musty smell from the air vents. It went away in a minute or two and I forgot about it for the day. Started up again today and same smell for a while then it was ok. Its been a hot summer in Minneapolis so AC was running a lot but now its cooled off and I just noticed the smell. Climate control set to automatic at 72 degrees and ac comes on automatically. Ideas?

next time, turn off A/C, but keep the fun running for a few minutes before parking.

I have not had that problem on my 03 C2. However, my BMW 745i suffers from that musty smell unless I periodically bring it to the dealer for a cleaning service. Dealer claims it's a mildew which collects in the AC ducts. They spray some gunk into the ducts and it works for about 3 months, then the smell comes back. They also suggested that the A/C always be used to prevent the accumulation. Dpesn't work for me. I'll be trading for an Audi S6 next month and I hope that won't be a problem.

my friend's BMW has the same problem, he went to autozone and brougt some sprey, which helped somewhat. i don't think this is a problem, but if you really want to get rid of the bad smell. park the car, open all the window, run the A/C to Hiheat, fan full spend for 15 minutes, this should work.

Here is what you do... Open your trunk and go through the process as if you are removing your cabin air filter. Take the filter out. Run the interior fan on high with all vents selected (defrost, front, feet). Now while the fan is blowing start spraying Lysol Disinfectant Spray (your choice of scent) into the opening where you took out the air filter. This will draw the disinfectant into the ducts where it will kill any mold, mildew, and bacteria that are causing the smell. Do this every few months ~6mnts to keep the problem away. Also it is a good idea to run your vents with the A/C off for a minute before you are ready to get out of the car to dry out the vents.

In addition to the above, you may be surprised to find that rodents have made a nest on the top of your cabin filter........... That puppy needs to be checked regularily, especially if you store the car for any period of time........

try to look for the airfilter....couldn't find it on my P...on my X5 it was easy and smell much better. Lysol rocks!!

Thanks guys...I did have the mouse nest in the filter earlier this spring so I have a new filter in there. It sounds like you guys know of the problem and I will take the steps you mentioned. Also I have a product called Atmosklear that is oderless so I may try that first..not sure I like any of the lysol scents crazykid mentioned. Thanks UCrazykid!!

Your welcome, anytime. The importance of using Lysol is that it is an air and surface disinfectant , not just an oder remover. You need to actually kill the odor causing mold, mildew, bacteria, etc. I do not think Atmosklear has a disinfectant in it.

I think you are correct. I'll go with Lysol!

I have the same problem. Will try your suggestion UCrazykid. Thanks ! Now for the stupid question.... Where exactly do I find the cabin filter? I know it's under the hood but where? Anyone have an informative picture you could post? Thanks!

Directions are here. http://www.renntech.org/forums/index.php?showtopic=7058 You have to register (free) and login to view at renntech.org

Ok, I had some time so I will put it here. Thanks Loren for the write up. From Renntech.org The panel is on the Left (passenger) side as you face the trunk from the front of the car. Tools you will need: T25 Torx drive 1. Remove T25 Torx screw that holds the panel cover in place (passenger side front trunk). 2. Remove the panel cover. 3. Remove the particle filter upwards and out of the housing guide. Assembly is opposite of disassembly.

Thanks a million UCrazykid. I actually searched at Renntech for a long time without success before I posted here (I'm a member there too.) Hope to see you again at SR on the 22nd for the big P-car meet. Your car sounded so good with the PSE that it totally ruined my new MKII mod for me. A PSE is in the near future for me

hehehe, sorry to hear about the PSE ruining your day. I'll miss the 22nd, I will be on vacation with the family. Take pictures! The directions are listed under "Pollen filter replacement" at Renntech.

UCrazyKid, the instructions were very helpful. Thanks! Very easy to do but it sure helped to located where the filter was placed. I'll bring the camera for sure. Don't want to miss the opportunity to take pics of 100+ Porsches barreling down 101. That will be a beautiful sight

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ahh! that would be the same musty smell that was sucked into the vents at the last drive. you think? souds like someone needs dial.

That musty smell is pretty well known to BMW owners. On one of my BMWs, some years back, the AC wasn't very strong when the car was sitting in traffic, so I tended to use the "recirculate" feature, which recirculates the inside air rather than drawing in the hot air from the outside. Using the recirculate feature massively accelerates this must problem. After I found this out, I avoided using it on that car and other BMWs that I subsequently bought and have not had this problem on those cars. Of course, in the interim, the AC got much better, so there didn't seem to be much need to use recirculate anyway.

More information and a possible solution at airsept.com. Read about their EED, Electronic Evaporator Dryer.

If the problem is mildew that has collected in air vents, a solution of water with 1/3 bleach does the trick better than many prepared products. It may not smell as much, either. Remove carpets where it might drip. Spray it into the vents and in the air inlets. Let it stand for about 20 minutes. Repeat. Then drive the car for a while to dry the system out. Sometimes the smell can indicate that a scupper (drain for water/condensation) has become clogged and the system is now collecting water at a low spot. No doubt Renntech has diagrams that will show if there are drains that might have become clogged. A fairly common problem across all marques in the Southern states.

Oggie, Very good suggestion. We have found that customers that always use recirculate, report the musty smell more often. Switching to outside air, seems to allevate the stale, musty air. It seems to be a common problem in the VW's as well and the techs also advise their customer to vary the type air flow.